author | valeriep |
Tue, 04 Sep 2012 18:41:06 -0700 | |
changeset 13672 | 604588823b5a |
parent 5506 | 202f599c92aa |
child 15010 | ec6b49ce42b1 |
permissions | -rw-r--r-- |
2 | 1 |
/* |
13672
604588823b5a
7044060: Need to support NSA Suite B Cryptography algorithms
valeriep
parents:
5506
diff
changeset
|
2 |
* Copyright (c) 1997, 2012, Oracle and/or its affiliates. All rights reserved. |
2 | 3 |
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
4 |
* |
|
5 |
* This code is free software; you can redistribute it and/or modify it |
|
6 |
* under the terms of the GNU General Public License version 2 only, as |
|
5506 | 7 |
* published by the Free Software Foundation. Oracle designates this |
2 | 8 |
* particular file as subject to the "Classpath" exception as provided |
5506 | 9 |
* by Oracle in the LICENSE file that accompanied this code. |
2 | 10 |
* |
11 |
* This code is distributed in the hope that it will be useful, but WITHOUT |
|
12 |
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
|
13 |
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
|
14 |
* version 2 for more details (a copy is included in the LICENSE file that |
|
15 |
* accompanied this code). |
|
16 |
* |
|
17 |
* You should have received a copy of the GNU General Public License version |
|
18 |
* 2 along with this work; if not, write to the Free Software Foundation, |
|
19 |
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
|
20 |
* |
|
5506 | 21 |
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
22 |
* or visit www.oracle.com if you need additional information or have any |
|
23 |
* questions. |
|
2 | 24 |
*/ |
25 |
||
26 |
package com.sun.crypto.provider; |
|
27 |
||
28 |
import java.math.BigInteger; |
|
29 |
import java.security.*; |
|
30 |
import java.security.spec.AlgorithmParameterSpec; |
|
31 |
import java.security.spec.InvalidParameterSpecException; |
|
32 |
import javax.crypto.spec.DHParameterSpec; |
|
33 |
import javax.crypto.spec.DHGenParameterSpec; |
|
34 |
||
35 |
import sun.security.provider.ParameterCache; |
|
36 |
||
37 |
/** |
|
38 |
* This class represents the key pair generator for Diffie-Hellman key pairs. |
|
39 |
* |
|
40 |
* <p>This key pair generator may be initialized in two different ways: |
|
41 |
* |
|
42 |
* <ul> |
|
43 |
* <li>By providing the size in bits of the prime modulus - |
|
44 |
* This will be used to create a prime modulus and base generator, which will |
|
45 |
* then be used to create the Diffie-Hellman key pair. The default size of the |
|
46 |
* prime modulus is 1024 bits. |
|
47 |
* <li>By providing a prime modulus and base generator |
|
48 |
* </ul> |
|
49 |
* |
|
50 |
* @author Jan Luehe |
|
51 |
* |
|
52 |
* |
|
53 |
* @see java.security.KeyPairGenerator |
|
54 |
*/ |
|
55 |
public final class DHKeyPairGenerator extends KeyPairGeneratorSpi { |
|
56 |
||
57 |
// parameters to use or null if not specified |
|
58 |
private DHParameterSpec params; |
|
59 |
||
60 |
// The size in bits of the prime modulus |
|
61 |
private int pSize; |
|
62 |
||
63 |
// The size in bits of the random exponent (private value) |
|
64 |
private int lSize; |
|
65 |
||
66 |
// The source of randomness |
|
67 |
private SecureRandom random; |
|
68 |
||
69 |
public DHKeyPairGenerator() { |
|
70 |
super(); |
|
71 |
initialize(1024, null); |
|
72 |
} |
|
73 |
||
74 |
/** |
|
75 |
* Initializes this key pair generator for a certain keysize and source of |
|
76 |
* randomness. |
|
77 |
* The keysize is specified as the size in bits of the prime modulus. |
|
78 |
* |
|
79 |
* @param keysize the keysize (size of prime modulus) in bits |
|
80 |
* @param random the source of randomness |
|
81 |
*/ |
|
82 |
public void initialize(int keysize, SecureRandom random) { |
|
13672
604588823b5a
7044060: Need to support NSA Suite B Cryptography algorithms
valeriep
parents:
5506
diff
changeset
|
83 |
if ((keysize < 512) || (keysize > 2048) || (keysize % 64 != 0)) { |
2 | 84 |
throw new InvalidParameterException("Keysize must be multiple " |
85 |
+ "of 64, and can only range " |
|
13672
604588823b5a
7044060: Need to support NSA Suite B Cryptography algorithms
valeriep
parents:
5506
diff
changeset
|
86 |
+ "from 512 to 2048 " |
2 | 87 |
+ "(inclusive)"); |
88 |
} |
|
89 |
this.pSize = keysize; |
|
90 |
this.lSize = 0; |
|
91 |
this.random = random; |
|
92 |
this.params = null; |
|
93 |
} |
|
94 |
||
95 |
/** |
|
96 |
* Initializes this key pair generator for the specified parameter |
|
97 |
* set and source of randomness. |
|
98 |
* |
|
99 |
* <p>The given parameter set contains the prime modulus, the base |
|
100 |
* generator, and optionally the requested size in bits of the random |
|
101 |
* exponent (private value). |
|
102 |
* |
|
103 |
* @param params the parameter set used to generate the key pair |
|
104 |
* @param random the source of randomness |
|
105 |
* |
|
106 |
* @exception InvalidAlgorithmParameterException if the given parameters |
|
107 |
* are inappropriate for this key pair generator |
|
108 |
*/ |
|
109 |
public void initialize(AlgorithmParameterSpec algParams, |
|
110 |
SecureRandom random) throws InvalidAlgorithmParameterException { |
|
111 |
if (!(algParams instanceof DHParameterSpec)){ |
|
112 |
throw new InvalidAlgorithmParameterException |
|
113 |
("Inappropriate parameter type"); |
|
114 |
} |
|
115 |
||
116 |
params = (DHParameterSpec)algParams; |
|
117 |
pSize = params.getP().bitLength(); |
|
13672
604588823b5a
7044060: Need to support NSA Suite B Cryptography algorithms
valeriep
parents:
5506
diff
changeset
|
118 |
if ((pSize < 512) || (pSize > 2048) || |
2 | 119 |
(pSize % 64 != 0)) { |
120 |
throw new InvalidAlgorithmParameterException |
|
121 |
("Prime size must be multiple of 64, and can only range " |
|
13672
604588823b5a
7044060: Need to support NSA Suite B Cryptography algorithms
valeriep
parents:
5506
diff
changeset
|
122 |
+ "from 512 to 2048 (inclusive)"); |
2 | 123 |
} |
124 |
||
125 |
// exponent size is optional, could be 0 |
|
126 |
lSize = params.getL(); |
|
127 |
||
128 |
// Require exponentSize < primeSize |
|
129 |
if ((lSize != 0) && (lSize > pSize)) { |
|
130 |
throw new InvalidAlgorithmParameterException |
|
131 |
("Exponent size must not be larger than modulus size"); |
|
132 |
} |
|
133 |
this.random = random; |
|
134 |
} |
|
135 |
||
136 |
/** |
|
137 |
* Generates a key pair. |
|
138 |
* |
|
139 |
* @return the new key pair |
|
140 |
*/ |
|
141 |
public KeyPair generateKeyPair() { |
|
142 |
if (random == null) { |
|
143 |
random = SunJCE.RANDOM; |
|
144 |
} |
|
145 |
||
146 |
if (params == null) { |
|
147 |
try { |
|
148 |
params = ParameterCache.getDHParameterSpec(pSize, random); |
|
149 |
} catch (GeneralSecurityException e) { |
|
150 |
// should never happen |
|
151 |
throw new ProviderException(e); |
|
152 |
} |
|
153 |
} |
|
154 |
||
155 |
BigInteger p = params.getP(); |
|
156 |
BigInteger g = params.getG(); |
|
157 |
||
158 |
if (lSize <= 0) { |
|
13672
604588823b5a
7044060: Need to support NSA Suite B Cryptography algorithms
valeriep
parents:
5506
diff
changeset
|
159 |
lSize = pSize >> 1; |
2 | 160 |
// use an exponent size of (pSize / 2) but at least 384 bits |
13672
604588823b5a
7044060: Need to support NSA Suite B Cryptography algorithms
valeriep
parents:
5506
diff
changeset
|
161 |
if (lSize < 384) { |
604588823b5a
7044060: Need to support NSA Suite B Cryptography algorithms
valeriep
parents:
5506
diff
changeset
|
162 |
lSize = 384; |
604588823b5a
7044060: Need to support NSA Suite B Cryptography algorithms
valeriep
parents:
5506
diff
changeset
|
163 |
} |
2 | 164 |
} |
165 |
||
166 |
BigInteger x; |
|
167 |
BigInteger pMinus2 = p.subtract(BigInteger.valueOf(2)); |
|
168 |
||
169 |
// |
|
170 |
// Handbook of Applied Cryptography: Menezes, et.al. |
|
171 |
// Repeat if the following does not hold: |
|
172 |
// 1 <= x <= p-2 |
|
173 |
// |
|
174 |
do { |
|
175 |
// generate random x up to 2^lSize bits long |
|
176 |
x = new BigInteger(lSize, random); |
|
177 |
} while ((x.compareTo(BigInteger.ONE) < 0) || |
|
178 |
((x.compareTo(pMinus2) > 0))); |
|
179 |
||
180 |
// calculate public value y |
|
181 |
BigInteger y = g.modPow(x, p); |
|
182 |
||
183 |
DHPublicKey pubKey = new DHPublicKey(y, p, g, lSize); |
|
184 |
DHPrivateKey privKey = new DHPrivateKey(x, p, g, lSize); |
|
185 |
return new KeyPair(pubKey, privKey); |
|
186 |
} |
|
187 |
} |